The invention concerns the technical sector of machines for packing articles, with particular reference to machines for packing stacks of disc-shaped articles, in particular tablets, in rigid cylindrical containers, especially tubes.
The prior art includes machines for filling and subsequently capping vertically arranged, rigid cylindrical containers of a tubular shape.
In these machines, containers coming from a supply line are loaded one by one onto a conveyor to be transferred firstly to a filling station and then, possibly through other intermediate stations, to a capping station, and finally to an outlet station.
At the filling station, a plurality of articles are inserted into the tubular containers, one-by-one and stacked one on the other.
This filling operation must necessarily be performed with the container at rest, the duration of the operation depending on the time required for a single insertion and on the number of insertions necessary to fill the container.
The other operations, performed in the stations upstream and downstream of the filling station, are carried out to coincide with the rest stage for the filling operation, even though the times required for these operations are inferior to the time required for filling.
In a first type machine, a single step conveyor can be used to advance the containers, while the rest period required between each advancement step must be calibrated on the basis of the time required for the longest lasting operation, that is, the filling operation.
A technical solution of this kind provides an extremely slow machine with unsatisfactory productivity.
A second type of machine has multiple operating organs in each station, acting at the same time upon a plurality of containers, with a conveyor activated with a multiple step corresponding to the number of containers handled at each stage.
In this way, a proportional increase in productivity is obtained in comparison with the first type of machine, with the same duration of the rest stage, but considerable constructional complications arise concerning the machine's operating organs: the greater the number of containers to be dealt with simultaneously, the more numerous these complications become.
A machine of this type provides reasonable, but not optimum productivity compared with market standards, and presents significant negative aspects both in terms of costs and operational reliability.